Control apparatus for internalcombustion engines



L. LEE, III

Nov. 9, 1948.

CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES 2 Shets-Sheet 1 Filed Aug. 22

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Nov. 9, 1948.

CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES 2 Sheets-Sheet 2 Filed Aug. 22, 1945 FIG.

INVENTOR. L57 HTUN L55 l7 D governing the characteristics of Patented Nov. 9, 1948'" CONTROL APPARATUS FOR INTERNAL- COMBUSTION ENGINES 1 Leighton Lee, H, West Hartford,

Conn., assignor,

by mesne assignments, to Niles-Bement-Pond Company, West Hartford, Conn., a corporation of New Jersey Application August 22, 1945, Serial No. 612,082 13 Claims. (Cl. 123-119) The present invention relates to control apparatus for internal combustion engines, and particularly to apparatus for controlling the fuel supply and the ignition timing on such engines.

An object of the present invention is to provide an improved means for controlling the delivery of a set of injection fuel directlyto the cylinders of an internal combustion engine.

Another object is to provide such improved pump delivery control mechanismwhich responds to the rate of flow of combustion air to the engine.

A further object is to tion pump delivery control trolling the delivery of the idling conditions;

- Another object is to provide idling and delivery control apparatus which provides for a fixed minimum delivery per stroke of the pumps under idling conditions.

Another object is to provide such fixed minimum delivery control means which may be selectively removed .to permit the pump delivery to be completely cut on.

Another object of the present invention is to provide, in a fluid motor operated control device, improved means for preventing hunting or overshooting of the motor.

A further object is to provide improved means for controllingthe ignition timingin accordprovide improved injecmechanism for conpumps under engine ance with the setting of the injection pumpdelivery control mechanism and in accordance with the rate of flow of fuel to the engine.

Other objects and advantages of my invention will become apparent from consideration of the appended specifications, claims and drawings, in which Figure 1 illustrates. caily, the principles of somewhat diagrammatimy invention as applied Pumps for supplyin Therefore there is established between the entrance l2 and the throat of venturi i4 a differential of air pressures, which is a measure of the velocity of the air flowing thru conduit III.

This diflerence of air pressures sets up a flow of air thru a secondary air passage which may be traced from .an impact tube 20 opening into entrance l2, thru a conduit 22, a restriction 24, a conduit 26, past a valve 28 into a chamber 30, and thru a conduit 32 to the throat of venturi M.

The valve 28 is positioned by a sealed flexible bellows 34, mounted in the chamber 30. The bellows 34 proper contains a fluid having an ap preciable cosfllcient of thermal expansion, so that to a fuel supply and ignition timing control syse tern for an internal combustion engine, and

Figure 2 is a view taken on the line 2-2 ure 1. looking in the direction of the arrows.

Referring now to Figure 1, there is shown antair conduit 10, thru which combustion air for an engine flows from an entrance l2, pasta venturi I 4 and a throttle I 6, to a discharge outlet IS, The outlet i 8 may deliver air either directly to the engine intake manifold or to the intake of the supercharger. In some cases, a supercharger may be provided anterior to the entrance 12.

The venturi l4 follows the well known laws such devices.

the position of valve 28 carries with both the pressure and temperature of the air in the chamber 30'. By positioning the valve 28 in accordance with the pressure and temperature of the air, it may be made to regulate the pressure drop across restriction 24 substantially in accordance with the mass of air flowing thru air passage l0 per unit time. This manner of pressure and temperature compensation is more fully described and claimed in the co-pending application of Milton'E. Chandler, Serial No. 490,281, flied June 10, 1943, and now Patent No. 2,393,144.

The pressure drop established across restriction 24 is communicated thru conduits 36 and 38 to chambers 40 and 42, respectively. The chambers 40 and 42 are separated by a flexible diaphragm 44 and are located in a pressure meter generally indicated at 43.

wardly on the diaphragm 44 due to the difierence in pressure in chambers 40 and 42 is a measure of the rate of flow of air to the engine. Attached to the center of diaphragm 44 is a valve stem 48, which extends thru another diaphragm 50 and carries a valve 52' on the opposite side of diaphragm 50. The valve 52 cooperates with an annular seat 54, and regulates the flow between an inlet chamber 56 outside the seat 54 and an outlet chamber 58 inside the seat 54. ,Fuel under pressure is supplied thru a conduit 60 to the inlet chamber 56, by means'to be described later.

If the air pressure diiferential acting on diaphragm 44 increases, the valve 52 is moved downwardly until the flow into the outlet chamber is so restricted as to increase the pressure in inlet chamber 56 sufliciently to balance the increased downward force of the diaphragm 44. Similarly, I

if the air flow decreases, the force acting downance the fuel phragm 50 auaaae opening movement has relieved the pressure in inlet chamber 55 suillciently so that the forces on the diaphragms are again balanced. It may therefore be seen that the pressure meter 46 operates to maintain a pressure in chamber 53 which is a measure of the rate of flow of air to the engine.

Fuel for the engine comes from a tank or other source (not shown) and flows thru a conduit 62, past an engine driven pump 64, a mixture control unit 60, a Jet system 60, and thru a conduit I to the injector pumps, one of which is illustrated at I2.

The pump 64 is provided with a pressure relief valve '24 which maintains its discharge pressure at a substantially constant value.

The mixture control unit 66 includes a disc valve 09 fixed on a shaft rotatable by means not shown. When the disc valve 69 is in the full-line position shown in the drawing, fuel can flow from the mixture control unit to the jet system only thru a conduit I8. When the valve 69 is moved to the dotted line position shown in the drawing, then fuel can flow thru both the conduit I8 and another conduit 00 to the jet system 68. The full-line position of the valve 69 is knownas the lean position of the mixture control, and the dotted line position is termed the rich position. The valve 68 may also be moved to a position wherein it cuts off all the flow of fuel to the jet system 60. This latter position is known as the cut-off" position.

Fuel entering the jet system 68 thru conduit 18 passes thru a fixed restriction or Jet 82, or a restriction 84 controlled by a valve 83, biased to a closed position by a spring 88. Fuel entering the jet system thru conduit 80 passes thru a fixed restriction 90. Fuel passing thru restrictions 8% and 90 also passes thru another fixed restriction 92. 1

The injector pump appearing at I2 is of conventional form, and includes a plunger 94 reciprocated by a cam 96, driven by the engine. The plunger carries a pinion 08, which mates with a rack I00. By reciprocating the rack I00 the plunger may be rotated on its axis. The plunger is provided with a helical groove cooperating with the inlet port thru which fuel is admitted to the cylinder ahead of the plunger. By rotation of the plunger, the point in the plunger travel at which the inlet port is closed and pumping begins may be varied. In this manner the quantity of fuel delivered per stroke of the plunger is controlled.

The rack I00 is positioned by a gear I02 operated by a fluid servo-motor I04. The motor I04 includes a piston I06 reciprocating in a cylinder I08. A connecting rod H0 connects the piston I06 to a crank arm H2 attached to a shaft II4 on which the gear I02 is fixed.

The piston I06 separates the cylinder I08 into two chambers, IIS and H8.

Fluid is selectively supplied under pressure to chambers H and H8 under the control of a valve mechanism generally indicated at I20. The valve mechanism, I20 includes a spool valve I22 extending therethru. At its left end the valve I22 is attached to a diaphragm I24 which separates two expansible chambers I26 and I28. At its right end the valve I22 is attached to a diaphragm I30 which separates a pair of expansible chambers I32 and I34. A pair of opposed springs l36and I38 may be used acting in opposite directions on the diaphragms I24 and 10, which is manually I municated to chamber drop across it her I34 acts to the left 4 I80 to aid in maintaining the valve I22 at its central position. Y Y

The chamber I26 is connected thru a conduit I40 to the conduit 22 leading to the impact tube 20. The chamber I28 is connected thru a conduit I42 to the fuel conduit 'l0'on the downstream side of the jet system 60. The chamber I32 is connected thru conduits I44, I45 and I48 to the fuel line on the upstream side of the jet system. The chamber I34 is connected to the conduit 80, wherein as previously described, the pressure is maintained proportional to the rate of flow of air to the engine. The conduit 00 receives its supply of fuel from conduit I44 thru restriction I50.

The conduit I40 provides a vent for chamber I20. It may be seen that the pressure in chamon the diaphragm I30 and therefore a force is applied to the left on valve I22 which is a measure of the rate of flow of air to the engine. At the same time the fuel pressure on the upstream side of the jet system is communicated to chamber I32, where it acts to the right on diaphragm I30. The fuel pressure downstream from the jet systemis com- I28 where it acts to the left on diaphragm I24. For a given area of a jet system open to the flow of fuel, the pressure is a measure of the rate of flow of fuel therethru. Therefore, it may be seen I that the net force acting to the right on valve I22 sufiiciently that the force due to the difference in the pressure in chambers I32 and I20 is a measure of the rate of flow of fuel to the engine. Therefore, the valve I22 is positioned in accordance with the balance of two forces, one proportional to the rate of flow of fuel to the engine and the other proportional to the rate of flow of air to the engine.

The pressure in chamber I26 is small as compared to the pressures in the other three chambers I28, I32 and I3il. Furthermore, it is substantially constant, as compared to the variations in pressure in the other three chambers. In addition, any changes in that pressure act on valve I22 in the proper direction to correct the fuel flow for variations in the density of the entering air. As long as' these two forces are balanced the valve I22 remains in the position shown in the drawing. If the air flow exceeds fuel flow, the valve I22 is moved to the left. This opens a path for the flow of motive fluid to the motor I04 from a suitable source such as a fuel pump or oil pump .thru a conduit I52, past the valve I22, thru conduit Ilia to chamber H6 at the left end of the motor cylinder I08. At the same time, chamber H8 at the right end of motor cylinder I08 is connected thru a conduit I56 and past valve I22 to a conduit I58 and anti-hunting valve mechanism I60 to a drain conduit I02. The drain conduit may, for example, be connected back to fuel or oil tank, as the case may be.

This position of valve I22 establishes a high pressure on the left side of piston I06 and a low pressure on the right side, thereby causing piston I05 to move to the right, rotating shaft H4 clockwise and moving the injector pump delivery control rack upward. This rotates the plunger 24 in a direction to increase the pump delivery. The increase of the pump delivery continues until the fuel flow thru the jet system is increased due to the fuel pressure differential across it, acting to the right on valv,e to its former valve I22 and thru conduit I56. Chamber H6 is then connected thru conduits I64 and I58 to the drain. This produces a movement of piston I06 to the left and a corresponding movement on the pump delivery control in a decreasing direction until the fuel and air flows are again balanced.

Under conditions of high engine load a small change in the position of the pump delivery control racks can produce a large change in the rate of fuel flow because of the high speed at which the engine is running and the rapid reciprocation of the injector pumps. In order to prevent the establishment of a hunting condition because of the rapidity of response from this system under such conditions, I have provided the anti-hunting valve mechanism illustrated at I60. This mechanism includes a-diaphragm I66 separating a pair of expansible chambers I66 and I70. Fuel at the pressure upstream from the jet system is conducted thru conduits I46 and I72 to chamber I10." Fuel at the pressure downstream from the jet system is conducted thru conduit I74 to chamber I66. The diaphragm I06 carries at its center a valve I76 which controls the passage of fuel from conduit I58 to drain conduit I62. This valve is biased open by a spring I10. When the fuel pressure differential across the jet system is small the spring I'IB holds valve I16 open and the motor I04 is permitted to move as fast as it can. As the rate of fiow of fuel thru the jet system increases the fuel pressure differential across it, acting on diaphragm I66, overcomes the spring I18 and moves valve I76 toward a closed position. This restricts the flow of fluid from the servomotor to the drain and thereby slows movement of the servomotor. In this way, the motor is prevented from running so rapidly as to establish a hunting condition.

I have provided means for establishing a fixed minimum pump delivery control so that when the engine is idling the pump delivery remains constant. Under such conditions the measurement of air fiow by the venturi is quite erratic because of the small flow of air compared to the large size of the venturi. Therefore it is desired to have the pump delivery independently controlled unde such circumstances. This is done, in the arrangement shown, by designing the springs I36 and I38 50 that they move the valve I22 in a pump delivery decreasing direction when the pressure in the chamber I34 is small, as is the case unde idling conditions. The servomotor I04 then tries to rotate the shaft H4 in the clockwise direction (as viewed in Figure 2) and does so rotate it until an adjustable screw I80 (see Figure 2) carried at the end of an arm I82 fixed on the shaftIM, engages a stop mem ber I84. 'The pump capacity cannot then further decrease.

An extension of shaft I6 operates, thru an arm I66 and a link I88, an arm I90, which is freely rotatable on the shaft H4. The arm I90 is provided with a projection I92 (see Figure 2). The stop member I64 is pivotally mounted at I94. This stop member is provided with three substantially radially projecting fingers I96, I98 and 200. A coil spring 202 encircles the pivotal mounting I84 and has its opposite arms projecting so that one engages a stationary frame member 204, and the other engages the finger I96. The spring 202 thereby biases-the stop member I64 for clockwise rotation as viewed in Figure 2 so as to maintain the finger 200 in engagement with the frame 204. This maintains the finger I99 in the path ,of movement of screw I80, so as to determine the minimum delivery setting of the injector pumps. The finger I90, however, lies in the path of movement of the projection I92 of arm I 90. I The relationship is such that when the mixture control shaft is moved to its cut-off position, projection I92 engages finger I98 and rotates the stop member I84 counterclockwise against spring 202, thereby removing the finger I 96 from the path of the screw I90 and permitting the pump delivery control to move to its zero delivery position.

It may be noted that when the mixture control It is moved to cut-off the fuel pressure differential across the jet system becomes very high so that the valve I22 is moved in a pump delivery decreasing direction. Therefore, the servo-motor I 04 promptl moves the pump delivery control to its zero delivery position and the stop I64 no longer interferes with this movement.

When the engine is not running, it is desirable to be able to position the pump delivery control mechanism manually. Therefore, I have provided a clutch mechanism which is operable to connect the pump control mechanism to the mixture control shaft 76 when the engine is not operating. This clutch mechanism is showngenerally at 206 in Figure 1. It includes a casing 208 separated into a pair of expansible chambers 2) and ii? by diaphragm 2H5. The diaphragm 2I4 is biased to the right by a spring sleeve 2 I8.

2I6. The diaphragm 2M carries at its center a sleeve 2I6. This sleeve 2I6 has a central bore with a pair of diametrically opposite projections 2Ij9 extending into the bore. vA movable clutch member 22I is mounted in the bore of sleeve 2I8.

The member 22I is provided with a circumferential groove to receive the projections 2I9.' The member 22I may be assembled with sleeve 2 I8 by aligning the projections 2I9 with a pair of notches 260 in the surface of member MI and inserting the member 22I thru the sleeve until the projections enter the groove on member 2I9 and then rotating the member 2I9 relative to The member 2I9 has a projection 220 which mates with a recess 222 formed on the hub 224 of the arm I90. The shaft II4 projects thru'the hub 224 and the sleeve 2I8 and carries at its end a clutch member 226 including a pair of diametrically opposite projections 228 extending toward the sleeve 2 I8. The notches 230 on the clutch member 22I are adapted to receive the projections 228.- The chamber M2 is supplied IlI with fuel from the discharge of the pump 64 thru conduits I48, I66 and 232. The chamber 2I0 is vented to the atmosphere as shown at 234.

When the engine is not running there is substantially atmospheric pressure in the chamber H2 and spring 2 I6 then moves the diaphragm 2| 4 and sleeve 2 I6 to the right, so that projection 228 may enter the recess 230. Thereafter, the hub 224, the clutch member HI and the clutch member 226 rotate together. so that operation of the mixture control shaft 16 results in changing the position of the pump capacity control rack. As soon as the engine starts, fuel under pressure is supplied to chamber 2I2, where it acts on dia- 7 and the pump delivery control shaft H4 are thereafter separately movable.

I have provided an arrangement whereby the ignition timing control may be coordinated with the pump delivery control. Arm 236 is pivotally connected to the end of the rack I thru a suitable pin and slot connection. The arm 236 is attached to a shaft 238 carrying a cam 280. The cam 240 cooperates with a follower 242 which tensions a spring 244 acting on one end of lever 246. The lever 266 is attached at its center to a shaft 248 connected to any suitable ignition timing control device. The opposite end of lever 246 is connected thru a suitable pin and slot connection to a rod 250 positioned .by diaphragm 252. The diaphragm 252 separates two expansible chambers 254 and 256. The chamber 254 is connected thru a conduit 258 to the fuel line at the downstream side of the jet system, and the chamber 256 is connected thru conduits 260, I46 and I48 to the fuel line on the upstream side of the jet system.

From the foregoing, it may be noted that the ignition timing control ispositioned by the fuel pressure diiferential actingin opposition to the pump delivery control position. In an injector pump system two factors determine the fuel pressure difierential, one. of these is the pump delivery control position, and the other factor is the engine speed. By placing these two factors against each other in this ignition timing control, it is possible to regulate the ignition timing in accordance with engine speed. The cam 240 may be controlled to provide ignition control according to any desired function of engine speed.

.While I have shown and described a preferred.

embodiment of my invention, other modifications thereof will readily occur to those skilled in the art, and I therefore intend'my invention to be limited only by the appended claims.

I claim as my invention:

1. A fuel supply system for an internal combustion engine, comprising injection pump mechanism for supplying fuel to the cylinders of said engine, means for varying the delivery of said pump mechanism, motor means for operating said delivery varying means, a conduit for combustion air flowing to said engine, means associated with said conduit for producing two unequal pressures whose difference is a measure of the rate of flow of combustion air to said engine, a conduit for fuel flowing to said pump mechanism, a metering restriction in said conduit, an expansibie chamber, a restricted inlet passage for conveying fuel from said conduit to said chamber, a restricted outlet passage for said chamber, means for varying the restriction in one of said passages in response to the difference of said unequal pressures so as to vary the pressure in said chamber as a function of the rate of air flow, and means responsive to the pressure in said chamber and to the fuel pressure differential across said meterin restriction for controlling said motor means. 7 v 2. A fuel supply system for an internal combustion engine, comprising injector pump mechanism for delivering fuel to the cylinders of said engine, means for varying the delivery of said pump mechanism between zero'delivery and maximum delivery, means responsive to the rate of combustion air flowing to said engine for operating said delivery varying means, and means for limiting the'minimum delivery which can be established by said delivery varying means at a value greater'than zero delivery.

mechanism, cut-off valve means for closing said conduit, and means operable concurrently'with movement of said cut-oil valve means to closed position to render said stop means ineiIective so that said delivery varying means can move to its zero delivery position. a

4. A fuel supply system for an internal combustion engine, comprising injector pump mechanism fordelivering. fuel to the cylinders" of said engine, means for varying the delivery of said pump mechanism including a rotatable shaft, an arm fixed on said shaft, a manually movable arm rotatable on said shaft, stop means for limiting the movement of said fixed arm and said shaft, cam means on said manually movable arm for engaging said stop means and moving it out of the path of movement of said fixed arm, and clutch means operable to engage said manually movable arm with said shaft for concurrent movement. I 5. A fuelsupply system for an internal combusion engine, comprising fuel injector pump mechanism for delivering fuel to the cylinders of said engine, means for varying the delivery of said pump mechanism, fluid motor means for operating said delivery varying means, conduit means for supplying motive fluid to said fluid motor means, a conduit for fuel flowing to said pump mechanism, a metering restriction in said fuel conduit, means for variably restricting said motive fluid supply conduit means, and means responsive to the fuel pressure difi'erential across said metering restriction for operating said variable restricting means to increasingly restrict said motive fluid supply conduit as said fuel pressure differential increases so asto prevent huntnism for deliverin fuel to the cylinders of said engine, means for varying the delivery per engine revolution of said injector pump mechanism, a conduit for fuel flowing to said injector pump mechanism, a metering restriction in said fuel conduit, means for controlling the ignition timing of said engine, means operable concurrently with said delivery varying means to operate said ignition timing control means to advance said timing as said delivery is increased, and means' responsveto the fuel pressure differential across said metering restriction for operating said ignition timing control means to retard said timing as said fuel pressure differential is increased.

'1. A fuel supply system for an internal combustion engine, comprising injection pump mechanism for supplying fuel .to the cylinders of said engine, means for varying the delivery of said metering restriction in said conduit, an expansible chamber, a restricted inlet passage for conveying fuel from said conduit to said chamber,

a restricted outlet passage for said chamber;

means for varying the restriction in one of said passages in response to the difference of said unequal pressures so as to vary the pressure in said chamber as a function of the rate of air flow, and means responsive to thepressure in said chamber and to the fuel pressure differential across said metering restriction for controlling said motor means so as to increase the pump delivery when said chamber pressure increases and to decrease the pump delivery when said fuel pressure differential increases.

8. A fuel supply system for an internal combustion engine comprising a conduit for combuslion air flowing to said engine, means associated with said conduit for producing two unequal pres sures whose difference is a measure of the rate of flow of combustion air to said engine, a conduit for fuel flowing. to said pump mechanism, a metering restriction in said conduit, means for varying the fuel flow thru said fuel conduit, an

expansible chamber, a restricted inlet passage for conveying fuel from said conduit to said chamber, a restricted outlet passage for said chamber, means for varying the restriction in one of said passages in response to the difference of said unequal pressures so as to vary the pressure in said chamber as a function of and means responsive to the pressure in said chamber and to the fuel pressure differential across said metering restriction for controlling said fuel flow varying means.

9. Control apparatus for an internal combustion engine, comprising injector pump mechanism for delivering fuel to the cylinders of said engine, means for varying the delivery per engine revolution of said injector pump mechanism, a conduit for fuel flowing to said injector pump mechanism, a metering restriction in said fuel conduit, means for controlling the ignition timing of said engine, means operable concurrently with said delivery varyinganeans to yieldably apply to said ignition timing control means a force acting in a timing advance direction and increasing as said delivery is increased, and means responsive to the fuel pressure differential across said metering restriction to apply a force acting in a timing retarding direction to saidignition timing control means, said last-mentioned force increasing as said fuel pressure differential is increased.

the rate of air flow,

10. A fuel supply system for an internal combustion engine, comprising injection pump mechanism for supplying fuel to the cylinders of said engine, means for varying the delivery of said pump mechanism,'fiuid motor means for operating said delivery varying means including a pair of expansible chambers separated by a movable means including a high pressure connection and a low pressure connection, control valve means for said fluid motor means, said control valve means having a normal position in which said wall, a motive fluid supply system for said motor co 2388569 delivery varying means, said first bar in a delivery decreasing direction and theremotor means is not connected to said motive fluid supply system and operable upon movement from said normal position to connect one of said chaming said clutch means to connect said control device and said delivery varying means, and means responsive to operation of said engine for operating said clutch means against said second spring means to disconnect said control device from said spring means being effective when said engine is not operating to move said control valve means to an open position so that said chambers are connected 'thru said fluid supply system, thereby making said wall and said delivery varying means easily movable upon actuation of said control device.

11. A fuel supply system for an internal combustion engine, comprising injector pump mechanism for delivering fuel to the cylinders of said engine, means for varying the delivery of said pump mechanism including a member movable between zero delivery and maximum delivery positions, a stop movable 'between an active position wherein it limits the movement of said memby establishes the minimum fuel delivery and a retracted position whereinit permits movement of said member to said zero delivery position, means biasing said stop toward said active position. and manually operable means for moving said stop to said retracted position against said biasing means.

12. A fuel supply system as in claim 11, including means responsive to the rate of flow of combustion air to said engine for operating said delivery varying means.

13. A fuel supply system as in claim 11, including means associated with said stop to adjust the value of minimum fuel delivery determined by said stop.

LEIGHTON LEE, 11.

REFERENCES CITED UNITED STATES PATENTS Number Name Date 2,341,257 Wunsch Feb. 8, 1944 Baker Nov. 13, 1945 roman PATENTS Number Country Date Australia May 2, 1941 

